Create spectrograms from a bunch of audio files, try also with "rate 4k" to "zoom" bottom part

do.sh

#!/bin/bash
a=0
for i in ~/music/*mp3; do
    ((a++))
sox \
    "$i" \
    -n remix 1 spectrogram \
    -m -h \
    -p 2 \
    -z 80 \
    -s \
    -d 60 \
    -x 1000 \
    -c "" \
    -o ${a}.spectrum.png
done